1. Field of the Invention
The present invention comprises an improvement in programmable phonograph record turntables and changers such as that shown and described in copending patent application Ser. No. 682,079 filed Apr. 30, 1976 and assigned to the assignee of the present invention and relates, in particular, to improvements in the record land detecting systems of such devices.
2. Brief Description of the Prior Art
Most musical recordings are sold in the form of disc-type photograph records where a plurality of sound track selections are spaced apart by unrecorded land areas which include an unrecorded groove to carry the stylus to the next sound track selection. Often a user of this type of phonograph record will want to hear fewer than all of the sound track selections on a particular record. Various record players have been proposed which are designed to permit a user to select a certain number of sound tracks to be played. The known prior art devices include U.S. Pat. Nos. 2,952,464 to Stimler, 3,368,080 to Nakagiri and 3,937,903 to Osann. It has been found that the amount of light which will be reflected by a particular unrecorded land area will vary greatly from record to record and even between proximate areas of the same sound track. Thus, there is a need for greater reliability in programmable phonograph devices and the present invention is directed toward such a device.